<?php
function get_user_array($coll, $id){
    return parse_user( $coll[ 'users' ]->find( array (
            '_id' => new MongoId( $id ) 
    ) ) );
}
function parse_user($data){
    $author = current( iterator_to_array( $data ) );
    return array (
            'id' => (string) $author[ '_id' ],
            'nick' => $author[ 'nick' ] 
    );
}